1. Field of the Invention
The present invention relates to a power supply transformer with high efficiency, and especially to a power supply transformer of which the iron core is a closed annular member made by continuous winding of a silicon steel sheet. By using a manufacturing technique for the present invention, the present invention can be more applicable for a miniaturized transformer with a low power of less than 50 W made from annular linear member.
2. Description of the Prior Art
In the present designing for a conventional linear power supply transformer, an iron core is formed by punching a big silicon steel sheet into sheets with shapes of “E” or “I”; then these sheets are stacked for assembling. In punching for such an iron core of the conventional transformer, directionality of the silicon steel sheets will be damaged; and in completion of the punching, the gaps between every two neighboring “E” sheets or “I” sheets will create larger energy of magnetizing and consumption of the iron core, and the efficiency of the power supply will be lowered.
And more, by the fact that the magnetic conductivity of a conventional power supply transformer can only reach 1.2˜1.4 T (tesla), a primary and a secondary copper wire coil of high specifications made by winding must be adopted, this results larger weight and volume of the entire power supply transformer, thus inconvenience of use is resulted.
For the known annular transformers, they can only suit large scale transformers because of the problem of manufacturing procedure for them. Such large scale transformers have mylar plastic tapes for enveloping and separating for insulation, then their coils are wound. During enveloping by the mylar plastic tapes and coil winding conventionally, quite large manpower is required; this is time consumptive and has low efficiency, and is not economic to be used to produce miniaturized power supply transformers, thus improvement is necessary.